Concrete sidewalk.



DONALD G. MACDONALD, OF DETROIT, MICHIGAN.

CONCRETE SIDEWALK.

Specificaton of Letters Patent.

Patented June 11, 1907.

Application filed November 19, 1906. Serial No. 344,()13.

To all whom, Tit 'may concerns Be it known that I, DONALD G. MACDON- ALD, a citizen of the United States, residing at Detroit, county of WVayne, State of Michigan, have invented a certain new and useful Improvement in Concrete Sidewalks; and I declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this speciication.

This invention relates to concrete sidewalk Construction, and has 'for its object improved forms of concrete members which entirely avoid the use of wood, and which are not only cheaper in the first instance, but improve structurally with age.

In the drawingsz-Figure l, is a perspective of a section of walk with the stringers extending past the same at each end. Fig. 2, is an elevation of the end of the walk, showing the relative position of planks and stringers. Fig. 3, is a section of the same. Fig. 4, is a sectional elevation at right angles to the plane of Figs. 2 and 3, and looking lengthwise of a sidewalk as completed.

l and 2 represent longitudinally extending stringers of concrete, grooved in their upper face, as at 3, throughout their length, and with their ends l and Q notched in complementary fashion to 'form a strong joint at their point of union.

4 are the individual planks of a walk along whose under surfaces extend integral projecting strips 5 near each end, which fit into the recessed portions 3 in the stringers. At each end the tread planks 4 extend beyond the stringers, the same as in the ordinary plank walk. The boards and stringers may each, or either, be reinforced as at 9, With any approved 'form of metal insertion, or they may be left without reinforcement, depending upon the strain which they are expected to carry.

6 are foundation blocks laid in the ground beneath the points of union of the stringer pieces. Like them, they are preferably of concrete, and they serve to prevent the stringers from sagging at these points. Each board has a lateral rib 4 on one edge, and a corresponding recessed portion l on the other, so that the boards may be fitted the I same as wooden boards.

This I regard as a desirable though not an indispensable feature. The cohesion of the boards, due to this, in addition to that caused by the projection of the strip 4. into the recess 3 in the stringers, makes the 'further use oi any securing means, such as nails, entirely unnecessary, especially il', just prior to the insertion of the strips 5, the recessed part 3 is smeared with a coating` of nearly liquid cement.

hat I claim is 1. In a conerete sidewalk, the combination of a tread member having integral projeeting holding strips near each end oi' its under surface, a plurality ol" rows ol' stringers having their upper su'l'aces grooved l'or the reception oi' said holding strips, and having the end portions ol' each stringer formed to interleck with the complementary ends oi' adjeining stringers, and supporting blCCkS Whereon the 'meeting ends of the stringers rest, substantially as described.

2. A conerete sidewalk, having in combination with unitary Stringer members of said material provided with a groove in their upper surfaces and adapted to interlock at their ends with those adjoining, blocks whereon said stringcrs rest at their ends. and concrete tread members provided with longitudinally extending rein'forcing strips and having projccting 'l'rom their under surface shoulders adapted te engage within the grooves in said stringers, substantially described.

3. In a concrete sidewalk, the combination oi molded stringer members having ends adapted to interlock with those adjacent, their upper surfaees being indented 'for the receptien of complementary projections, bloeks beneath the meeting ends ei' said stringer members, and concrete tread members having projecting portions on their under surfaces adapted to engage in said indentations, each having a complementary rib on one lateral edge and a recessed portion in the other lateral edge, substantially as described.

In testimony whereo'l", I sign this specification in the presence ol' two witnesses.

DONALD G. MAODONALD. lVitnesse/s ALIGE ToWNsEND, WILLIAM M. SWAN.

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